Machine tool



G. F. ESSON June 7, 1949.

MACHINE TOOL Filed March 29, 1944 HYD/2A uL/c PUMP ,m

N my T z y m T 5H c vo, l H a 3 A. s y n., P L o 5.- 2/ w W 4 s TH A 2 L/ 5 T .5 Y R 5 l 2 5 T 7 C l En" 4 E s c M -l L M Tw s a m A 5 TE w w+-- e rn .w 5c e ADV 6 9 |C s w 2 s 4 ,/.N 7 .r 7 P. M 2 P e o v .e C c@ N mm, mv ESI E wm//M @m m//y/A my, GY B G. F.l EssoN June 7, v1949.

MACHINE TOOL 4 Sheets-Sheet 2 Filed March 29, 1944 June 7, .1949. G, F ESSON 2,472,744

MACHINE TOOL Filed Maron 29, A1944 4 sheets-sheet s 20a. l o t Z/ y f [NEN TOR. F 1' g, 6 50mm/v foi/9555 -sso/v HTTOENE Y June 7, 1949.

G. F. E SSON MACHINE TOOL 4 Sheets-Sheet 4 Filed March 29, A1944 Patented `lune 7, 1949 UNLVFED`r PATENT' FFICE (StorioxrA Forbes? Essoin. Detroit, Mich., assigner to yEx-Gell-O Corporation, Detroit, Mich., a corpo.-

ralton. of, Michigan- 3 Claims. l

This invention Vrelettesgenerally''to class .oiz devices knot/nin; the art. as.v l.drilr units which are: frequently' mountedzon, 'az machinefloase (not shown-)f in association; witlof-,a work' holder (not shown) 13o-'constitute @machine toolvifor theper formanoeofioutting'operations;

MoreI particiilarly suontdrill; are used/torl rotating: and' 'axially' `moving' e.: tool lsuch as; is used' for drilling; .roam-ing` :or tapping. in a. 'cycle ncluding'rst, a cutting stroke.. and subsequently', aretract'ingfor returnstroke.

lOne object lof the invention fis to provide :a lini'directionally` 'rotatable' means for causing Areversible -a'xiall inovemenftoi acutting'toofl responsive to fa= reciprocating piston meanfsfwhie con stan't rotationfo'f thetool ismainteinedfby anni'- di'rectional driving means.

Other objects and advantageseotlieinveiiiiion will more kf-ully appear from *the vfollowing description takenl in "connection with 'the aceom c panying drawings, whidh z' Fig. '1' is fa diagrammatic illustration -of a pluf ralityo'i units:

Fig. 2 shows a wiring diagram ffor supplying and controling energy *to Vrotate the tools of a multiplicity yof electric motor' -drven `units* and to drive the pump/Which supplies the Fl'fiyd'raliliic"iuid pressure for reciprocating-the tools;

Fig. '3 is a horizontal sectionalview with 'cam cover plate removed, 'tai-ken-on"=1ine 3 3 ofFlg. 4 f

ofone of the units:

Fig. '4 is an rendl 'View Lof *the unit shown 4in Fig. 3; Fig. 5 is a transverse 'sectional vii-ew taken 'on line 15v`5of Fig. 3;

'Fig '6 is' -a sideA elevational View' of the 'unit shown 'in Fig. 4, with tcam lco'ver "plate removed;

Fig. 7 'is a topvp'l'anview oith'eunit with driving motor removed 'and' wi'fh'abelt guard; and

fii'g. 8i'safsideelevational m'ew opposite l:to that shown in Fig'. yffwitn"fbe1t'fguardin lf'a'ce.

"Referring 5to "the =crawings 'amd particularly .-t'o Figs. 3 `to 8' inclusive, 'tl-'re .unfit inolu'des Ya. housing f`r on which is mounted sa v,motor .F2 :arranged 'to drive a `pulley M thtotzglli'belt -M'ae-Whichrotates internally spln'ed, hollow hattfl in ''beaiin'gs 18. Bearings 1|81areffastene l. `n.refarisleemeTtla'whch is t'fixed in the inward end of .stepped bore fis fin housing 10. These hearings zpreoent aidalamovement of fshait 46 v"relative lthe :housing The forward (leitward `in Fig. (3) fend Iof the fbore :I9 supports .fan axially slidloie ibut non-erotatable quill20 :having eacentra'l shaitezz axially movable therewith and Arotatable therein ion :bearings 24. shaft ibas at its leftward 'or firm-ward send ia ill@ foil

snuck on like `'deo/ine 21|; for; holding a rotatableouttingrtool suehaaes a =driil;greameretc. and otite opposite end. a splirxed shaiftfextension- 2lil engageing thea internallyy splined :portion oi shaft 14.6, enabling the shaft 216.I to be -rotationally driven thereby while;- heing .axialiyf moved relation thereto with recinrooaton- :ofthe quilly2li'. o

About midway of the length ofv the'iquill, its; housing member Zn: provided. with. oppositelo extending trm'miorr members; 218', 3.0 fixed theretoy and' itat/ingr .ecylindrioalfl-yiormed: journai portions F32 tencompassesd bearing ,blocksi .34 heldthereon.lbysliomdersrI-S: 'Thef-bearingfblooks have'. parallel opposed faeesi tFig. 6): adapted to. 'slide inthe tworopenieridedslots Mhof a yoke member 42 isI piuoted :as at 4.4i .and be. :rotatedt there:shoutA hy 'interaction fvoff :al loam follower .roller liti and-Whe oem 58'. Roller 46 is mounted .aboutt-mictwayoi .yoke 'Maho' a; suitabl'e stud #8. A spring :52 (figs. v3 'and 15) which has i'tsvilxedf -endfattacired in. housing Till ascat :53, and its `inovelo'e end'attached to lthe outwardly extending of trunnion 230 constantly urges yoke '42 Ito "rotate: in ia olockwifse `fdir@etiolo- (see Fig. '6J vabout its 4pivot andT-Iikewisewurgesquill 20 toward its .retracted .or withdrawn position.

'Cam .'ilJi is mounted on :cross: shaft fll4 "which is rotatably 'supported son needle "bearings: "56l re ceive'd 'in a stepped, crossftbore `i58 vformed' nhimseclockwise direction I('as:seemin Fig. 6)a, a convene tional overrunning or one-way' driving clutch 'in' cluding roll-er .60 causesoam 50 to movewth the shaft; however, when shaft 54 `moves a clool'c= wise direction, vespecialiy'fafter camff'o'llower vroller i161 has passed yover the :drop-off `fpm-.tion '5011,01' cam "50 allowing the quill 12D to be retractedfto 'its i'nnnermos't position, `cam 150' fwill not 'move .with any clookwise lmovement of Ishaftid.

'Shaft 54 is'fformed .adjacentthe end opposite to-'thatsupport'i'ng the 'cam EEB-.'(f'Fig. 5()v Awithpinion `vteeth '62 :'(Fg. i8)y `Lwhich are engaged "by-rack teeth 6l formed on Ya meniberf' which ihas Jai: either end oppositely'acing pistons ist arranged toibe moved .in `rigl'rtvtfznd or zleftward direction;

in their fsurrounding there T0, .which .formed ifin housing ll'xby alternative `:application 4of ,.ui

pressure'onitheriopposedouterffaoes. 'The source *of AYfluid pressure .as best seen 'rin Fig. i1 may conveniently be the "conventionala constant displacement .'fpump mi) disohen'ging` into a. branched l'conduit HH Thaving associated 'tlierel with a 'conventional zpressure :relief 'valve M2 fand in aassooiation also with a @conventional "three position :reversingfvalve +04 which fis adapted to 3 connect pressure conduit lll or exhaust conduit ||2 alternatively to conduits |05 or H0. In the instance shown, valve |04 may be placed in one extreme position by energization of solenoid 12 causing iiuid pressure to be applied to the left face (Fig. 8) of piston 68 through branched conduit |05 while the right face of piston 60 on the opposite end of the rack S6 is relieved to the supply tank |08 through the branched conduit ||0 thus causing the quill 20 to be advanced until cam 50, in its contact with roller 40, has passed the drop-off point 50a causing quill 20 to retract to its innermost position under the action of spring 52. Upon energizing solenoid 14 (and deenergizing solenoid 12), iiuid pressure is applied to the right face of piston S8 through conduit |0|, the left face being relieved to the supply tank, pistons 68 and rack 66 are caused to excecute a recovery stroke without movement of cam 50 or quill 20.

The rate of pressure uid displacement to the leftward or feeding face of piston 68 is controlled by an adjustable orifice 16 which controls the flow area in the path of pressure fluid entering the housing l0 at 18 from conduit |06. Entry 18 communicates internally of housing i0 with branched passage 80 and after passing the adjustable orifice 16, which may be of any conventional sort, passes into branched passage 82.

It is here to be noted that, during in-flow at entry 18, the pressure in passage 80 tending to seat ball check 84 in addition to the downward force of its associated spring 85, is always greater than the lifting pressure in passage 82 causing all fluid which reaches passage 82 to have iirst passed restricted oriflce 1B. The reduced pressure of passage 82, which is then applied on the feeding face of piston 68, may therefore, be controlled to cause the forward stroke of piston 88 and quill 20 to be accomplished at the desired velocity. During the last described movement of piston 68, the exhaust fluid displaced by its advancing rightward face flows through passage 83 (Fig. 8) and port 86, both formed in housing I0. into conduit H0, through valve I 04, and exhaust conduit I I 2 to the supply tank.

When the valve |04 is reversed by energizing solenoid 14 and deenergizing solenoid 12, pressure fluid from branched conduit |0| is admitted to conduit H0 and to the right face of piston 88 causing leftward movement thereof. The exhaust fluid displaced by the leftward advancing face of piston 68 is forced into passage 82 from which a negligible portion thereof may move through restricted orice 10. passage 80 and port 18, through branched conduit |06, valve |04 and exhaust passage ||2 to the supply tank. However. bv far the greater portion of the exhaust fluid displaced by the advancing face of piston 68 bypasses the orifice 1B. Virtually without restriction, by lifting the check valve 84 and after traversing7 passage 80 returns to the supply tank through the path previously traced. It may. therefore. be seen that the forward or feeding stroke of the pistons 68 and the quill 2|! is always accomplished at a controlled rate as determined by the adiustrnent of orifice 1S, and the return stroke of the quill 20 takes place at relatively rapid velocity due to the drop-Dif portion 50a of cam 50 while pistons 58 and cam 50 are still moving in their forward or feeding direction.. Cam 50 in normal operation never has a reverse or recovery movement but, because of the oneway clutch including driving roller 6Fl and the bypassing of orifice 18 when valve |04 is reversed,

.4 the recovery stroke of pistons 68, which may not be instituted until an appreciable time after quill 20 has executed its retractive stroke, may be accomplished at a rapid rate in relation to its forward feeding movement.

Cam 50, which may be of any desired shape is, in Fig. 6, shown of a shape which is advantageous for the performance of deep drilling operations. During the passage of a relatively quick rise portion 50c in contact with the follower roller 4G, the point of the drill (not shown) is rapidly brought into proximity with the workpiece (not shown). During passage of the next slow rise portion 50d over the roller 4E, the tool is advanced into the work at a feeding speed. When the depression 5017 contacts the roller, the drill is retracted a predetermined amount for a brief time to cause the drill chip to be discontinuous and to allow the previously formed chip to be cleared from the drilled hole by translatingaction of the spiral flutes of the drill (not shown). While the cam follower 46 contacts successively the portions of the cam numbered 50j, 50c, and 50g, the drill is given respectively an axial advance at feeding speed, a second chip breaking retraction and a final infeeding movement to its ultimate depth which is completed just before the drop-off portion 50a causes the complete retractive stroke. These last said movements are accomplished while the feed control pistons 68 are still moving at controlled speed in a forward direction and, as pointed out in a later illustration, this construction gives rise to a unique advantage when a multiplicity of drilling units is required to operate simultaneously as a singly controlled group though the duration of their several cutting traverses may not be exactly coextensive.

To enable a multiplicity of units to be simultaneously operated and controlled by one electric circuit common to all, each unit contains a limit switch 88 which may be operated as shown in Fig. 6 by a connecting rod 90 pivoted at one end to yoke 4'?. below its point of oscillation 44 and at the opposite end to rod 92 being thus adapted to reciprocate the rod 92 and its conically formed operator 94 which lifts switch plunger 06 closing the said switch when the quill 20 is in its fully retracted position and allowing the switch to remain open otherwise. The limit switches 8B of Fig. 6 are indicated respectively for the three units 2, 3 of Fig. 1 by the series connected switches LSI, LS2, LS3 of Fig. 2.

The unitary control of a multiplicity of units may well be illustrated by Figs. 1 and 2 in which the pump |00 of Fig. 1 is driven by the motor M of Fig. 2 and units 2, and 3 of Fig. 1 are respectively driven by MI, M2, and M3 of Fig. 2. After closing the main switch of Fig. 2 connecting the lines LI, L2, L3 to the supply, the circuit is conditioned for operation. The hydraulic pump motor M may then be started by momentarily depressing the Hyd. start button connecting lines 2, 3. A circuit is then completed energizing the solenoid HYD via conductors l, 4, 3, 2. The last named solenoid closes all normally open contactors identified by HYD and starts hydraulic pump motor M which drives pump |00 supplying pressure through conduit ||l| to valve |04. The connection of conductors 2, 3, as by closing of the sealing contacter HYD, is a prerequisite to starting the several respective unit driving motors Ml, M2, M3 by momentarily depressing the Start sp. button completing a, circuit through solenoid SP via conductors I, 6, 5, 3 (which last has iingza @yale including:infeedingcaml return :movements tof ,several .units :2, .3 which may .be tdpne tbynnomentarily closing the :normally tunen .-tart myc-1e rbutton .adapted :to jjoin conductors im li, I. "Fheirst effect ofdenressng this ibuttonris tboaopenithelower,contactstofthemormallyiclosed manually operable ucontacter .which opens rthe mircuitrthnough which :solenoid @R2 is enersized at the end of theletraatnnstrnkeof the qullS 20 au! of the severalmnits. This `lcircuit'may be traced through I, CR2, I3, k2, 4the .tthree closed MttQhBsMSLLSLLSB, 3 :and 22. Upon -opening :the contact .between 12,. f lr, .rboth CR2-:ar1`d:the

Drills out solenoid 14 controlling the valve IM are w) deenergized in preparation for energization of the Drills in solenoid 'I2 which will take place in .the following manner.

Upon deenergizing solenoid GRZ, its normally closed contactor CR2 falls closed joining 5 (which is already hot) to 'I which is connected to 8 through the normally closed Safety contactor. Closure of the manual contactor joining 8, 9 energizes solenoid CRI and Drills in solenoid 'I2 shifting the valve |04 to start the cycle of the units I, 2, 3. Energization 'of solenoid CRI closes sealing contactor CRI so that connection between 8, 9 is maintained after the Start cycle button is released. Immediately upon start of the several units on their feeding strokes the respective-limit switches LSI, LS2, LS3 drop open, but as the several units reach the forward extremity of axial travel of their respective quills 20 and are retracted into their rearmost positions by their springs 52 after their cams 50 have passed the drop-off point 5ta, the respective limit switches LSI, LS2, LS3 are closed in the order determined by the'respective durations of the feeding movements of the several units. With the closing of the last of these limit switches, circuit is established from I through Drills out solenoid and solenoid CR2 via I3, I2, Il, I0, 3. The normally closed contacter CRZ which has connected 5, 'I is then opened deenergizing the Drills in solenoid and CRI. Valve |04 is thereby shifted into the position to cause return of all pistons E8 and the units will then remain at rest, in so faras axial movement of their quills is concerned, until the Start cycle button is again depressed.v

At any time during a feeding stroke all units may be retracted by depression of the Safety button which has an effect similar in all control respects to the closure of the last of the three limit switches LSI, LS2, LS3 above described. However, in the event of reversing pistons 68 before cam 50 has passed the drop-off point, the cams 50l will normally, under the inuence of spring 5.2 and due to their shape which results in forward movement of yoke 42 with forward movement ofthe cam, roll backward with backward movement of shaft 54, this emergency retraction oecasionng the only circumstance under which cam 50 has any reverse rotation.

It is also to be seen that upon depression of the Stop sp. button, the spindle driving motors MI, M2, M3 will be stopped and both solenoids 12 and I4 will be deenergized. The valve II4 will then centralize: preventing axial travel of the quills in either direction. Substantially the last said :occurrence lwill tbe americanos manning sof Iany one of the several (eight) overload protective tdevi'ces iin `fthe .circuit iincluding `2St0l3 hyd. .button with the exception l@that @the hydraulic ipump-fmotoraw-illealsotstop.

llt :willibe tunderstood -that modifications land lalternative `constructions lexemplie'd fby lthe eembodimentihereindescribed*mayibefmadetwith outdeparthrg fromithesspiit of'mymvention-"antl it -is ymy fintention `not @to :limit `the fscope #thereof except `as fthe lsame is `'defined 'in the 'appended claims.

I claim as l:my invention:

.1. 4rif-mazcloine toolhavingrin combinationfa'i'rortatableaand'axiallylfiftable toolsunporting'spin- '.dlt, Vsluiting;meansyieldablyiirgingsaid spindleto... .ward 'a retracted-position, 'power actuated. means 'foradvancing Vsaidispindleinaifeedirrg"movement -and "for're'l'easing'the spindle 'forretnrniby said springmeanasaidmnweactuatedrmeansincluding a cam fhaving a gradually sloping surface for effecting the feed of thespindle, said surface terminating in an abrupt drop-off to permit rapid return of the spindle by said spring means, a follower operatively associated with said spindle for shifting movement therewith and engageable by said cam for shifting said spindle in opposition to said spring means, a shaft rotatably supporting said cam, a rack member supported for reciprocation transversely of said shaft, a pinion rigid with said shaft and coacting with said rack, cylinder and piston means reversibly operable in a forward stroke at an adjustable slow speed and in a return stroke at a relatively rapid speed for reciprocating said rack to rotate said shaft alternately in opposite directions, means providing a oneway driving connection between said shaft and said cam to effect positive rotation of said cam and said shaft in one direction in synchronism with said forward stroke of said cylinder and said piston means, and to permit reverse rotation of the shaft during the return stroke of said cylinder and piston means to normal rest position while said cam remains stationary, and control means operable as said cam drop-off moves past said follower and in response to the return of said spindle to effect reversal of said cylinder and said piston means at the end of said forward stroke.

2. A machine tool having, in combination, a rotatable and axially shiftable tool supporting spindle, spindle retracting means, cam means including a rotatable cam and a separable follower associated with said spindle for advancing the spindle and maintained in cooperative engagement by said retracting means, said cam being shaped to impart to the spindle an initial rapid advancing movement and a subsequent slower feeding movement followed yby the release of the spindle for rapid return by said retracting means, pressure fluid actuated means for rotating said cam in one direction only continuously through one revolution to effect the foregoing sequence of spindle movements, said pressure fluid actuated means comprising a shaft rotatably supporting said cam, reversible cylinder and piston means operative in a forward stroke to rotate said shaft in one direction and alternately in a return stroke to rotate said shaft in the opposite direction, and clutch means operative to drivingly connect said shaft to 'said cam when the shaft is rotated in one direction and to release the shaft from the cam when the shaft is rotated in said opposite direction, and means responsive to the return of said spindle for effecting reversal of said cylinder 7 and piston means at the end of said forward stroke.

3. A machine tool having, in combination, a rotatable and axially shiftable tool spindle, means yieldably urging said spindle tov-Jard a retracted position, pressure fluid actuated means for advancing said spindle in a feeding movement and for abruptly releasing the spindle for rapid return by said retracting means, said pressure uid actuated means including a reciprocatory fluid motor, a shaft continuously rotated in synchronism with the movement of and alternately in opposite directions by said motor, a cam rotatably supported on said shaft and adapted to coact with a follower associated with said spindle, and means operative to drivingly connect said shaft and said cam for joint rotation when the shaft is rotated in one direction and to interrupt the connection when the shaft is rotated in the opposite direction.

GORDON FORBES ESSON.

REFERENCES CITED The following referenlces are of record in the le of this patent:

UNITED STATES PATENTS 

